1. Field of the Invention
Embodiments of the present invention relate to camera-based tracking of objects, such as a user's head, in which markers are tracked by the camera, the markers changing color depending on their orientation to the camera. The orientation of the markers, determined from their color, is used along with the angular distance between them in order to resolve the distance of the object from the camera. In particular, some embodiments relate to markers mounted on a user's glasses head being tracked by a video-game console's camera in order to provide realistic 3-D effects and other feedback to the video game.
2. Description of the Related Art
Video games have become more immersive as technology progresses. Video game consoles are often produced with state-of-the-art processors, extremely fast memory, and high-end graphics cards. Input controllers have evolved from simple knobs, joysticks, and button-based controllers to accelerometer-enabled controllers that a user can swing in his or hands or wear. Further input technologies involve a camera, usually mounted on top of a television, tracking a user's body, including tracking his or her head, torso, arms, and legs. Users can control such video games by simply moving their bodies or parts thereof. For example, a player of a skateboarding game can duck down so that he or she clears a virtual bridge.
Three-dimensional (3-D, or 3D) televisions help immerse users in events happening on their display screens. For such 3-D televisions, a user sometimes dons 3-D glasses. Earlier 3-D glasses included red and blue lenses for discerning an anaglyph. Shuttered 3-D glasses have lenses that rapidly and alternatingly switch between being opaque and transparent in synchronization with a display that rapidly shows left and right images. Other types of 3-D presentation technology exist. Many are similar in that they present a separate two-dimensional image to a viewer's left eye and a separate two-dimensional image to the viewer's right eye either contemporaneously or very rapidly (e.g., at 60 Hz) in order to trick the viewer's brain into interpreting the stereoscopic images as a 3-D environment.
Video games utilizing 3-D display technologies can immerse a player in a game through the use of 3-D effects on the screen. Furthermore, video game consoles with body tracking can use 3-D effects to coordinate a player's actual movements in the real world with his or her virtual movement in a displayed virtual world. Head tracking can be critical for games that render based on where a user's head is. For example, as a user steps toward the television in his living room, a video game console can render a 3-D virtual pyre on the television so that it appears like he moves closer to it.
Thus, tracking the location, orientation, and movement of a viewer or other user's head or body parts can be important for some video games, especially those that use head-tracking to render 3-D objects closer to the user. There exists a need in the art for more robust head tracking that is not too expensive for mass production.